If I’d had this design back when I was a cubicle-bound temp then, well, lets just say I would have been fired even sooner than I was. The Pencil Crossbow is one of the designs for the book Mini Weapons of Mass Destruction by John Austin.

The crossbow is fashioned from just four pencils, a biro and seven rubber-bands, cunningly combined to make a deadly-accurate launcher which is guaranteed to take somebody’s eye out. The book allows for some escalation of inter-office wars with trebuchets, catapults and even printable targets to practice before an all-out assault on your boss.